Cigarette smoking, like other forms of drug dependence, poses a significant health threat in the United States. Public awareness campaigns have expanded the public's knowledge of the consequences of cigarette smoking, and the majority of smokers express a desire to quit. However, the vast majority of smokers fail in their attempts to abstain from cigarette smoking;a failure of self-control. Our long-term goal is to further knowledge about the variables that influence failures of self-control in an effort to facilitate the development of comprehensive treatment programs for dependence on cigarettes and other drugs of abuse. We will examine the phenomenon of failed abstinence efforts in the context of preference reversals, a phenomenon where a larger and more-delayed reward is preferred to a smaller but less-delayed when both outcomes are temporally distal, but switches to the smaller reward as time passes and both rewards become more proximal. These preference reversals may provide a framework for understanding why a cigarette smoker plans to quit smoking, but fails to initiate or maintain a quit attempt. A mechanism called soft commitment has been proposed to prevent these preference reversals, where repeated choice for the larger, more-delayed reward while the reward is distal develops response persistence for that alternative that is maintained even as the reward becomes more proximal. We hypothesize that a soft commitment mechanism can prevent or limit preference reversals. In Specific Aim 1, we will determine if cigarette smokers exhibit earlier preference reversals than nonsmokers. In Specific Aim 2, we will compare different models of delay discounting on their ability to predict the temporal location of preference reversal. In Specific Aim 3, we will examine the efficacy of a soft commitment procedure in preventing preference reversals in cigarette smokers and nonsmokers. In Specific Aim 4, we will determine the efficacy of soft commitment procedures when a cigarette smoker is experiencing nicotine withdrawal. If soft commitment does prevent preference reversals in human cigarette smokers, such procedures might be modified to prevent preference reversals when the preference reversal results in failures of abstinence attempts.